Automatic variable choker



Patented Nov. 2, 1926.-

' UNITED STATES PATENT oFI cE.

ANTON FRANK BBOTZ, OF KOHLER, WISCONSIN, ASSIGNOR T0 KOHLEB COMPANY, OF KOHLER, WISCONSIN, A CORPORATIQN OF WISCONSIN;

AUTOMATK? VARIABLE cnoxna.

Application filed January 11, 1924. Serial No. 685,859.-

This invention has for its object to facilitate the starting 01f an automatic gas-enginedriven generating plant of the demand starter type by providing for automatically choking the carbureter of the engine during the cranking of the engine .followed by a period during which the carbureter is partially choked, which period will continue until the "engine becomes warm.

It is well recognized practice in the o'peration of gas engines inautomobiles that dur ing cold weather best results are obtained by chokin eifects of varying degrees, the greatchoking the carbureter during cranking and retaining-a partial choking condition until the engine has become sufliciently warm. It isthe purpose of this invention to provide automatic means for accomplishing this practice in'an automatically controlled generating unit plant and thereby avoid a repeated cranking operation occasioned by the removal of thechoking efiect entirely as soon as the engine is cranked.

' With these objects in view the invention contemplates the use oi an electricall controlled choking device capable of pro ucing est cho ing eflectto be produced during the crankin operation and referabl controlled %ya circuit establis ed b t e motor starting switch and a lesser c okin effect produced by a circuit controlled y a thermal switch on the engine so as to be discontinued when the engine is sufiiciently I warm to require no chokingmfl'ect.

Whi e the invention -1s especially applicable to internal combustion engine driven farm lighting and ower lants, it is not limited thereto but 1s suita le for use with internal combustion engines generally;

' With the above and other objects in view the invention consists in the automatic vari-v able choker for internal combustion engines as herein claimed and all equivalents.

Referring to thd accompanying drawing, the figure constitutes a diagram of a generating plant containing the automatic variable choker of this invention.

In the drawing is shown a generating unit approximately conforming with actual practice and fully described in my co-pending application for starting field for enerating units, Serial Number 698,110, filed arch 10, 1924, and regarding much of which it will be sufficient for the purpos s of this case to merely mention the .names of parts without further explanation. y

In the drawing, 10 indicates a generator driven by an internal combustion engine, the throttle valve 11 of which is controlled b a solenoid having windings connected wit the generator windings, as will be described. The generator, as shown, is of the shunt type and-supplies the mains 12 containing'lamps 13 or other translating devices. The shunt field w inding l tof the generator is opposed by a bucking series field winding 15. The solenoid comprises a series coil 16 opposed by a voltage coil 17 and the solenoid core 21-operates" the throttle through a bell crank lever 23 and a link27 and is under the influence of a spring 25., r

A resistance 30 is connected in series with the shunt field winding 14 of the generator.

of a s ring-retracted switch 53 with a wire 54 lea ing to the bucking series field 15. In practice switch 53 constitutes a solenoidoperated starting switch closed only during the starting operation, i

A connection is shown for placing. the battery acrossthe mains with a resistance 55 in series therewith and controlled by a switch 56 for recharging the battery from the generator, the resistance 55 being necessary ined and its other terminal connected by means.

a stem 60 carrying a solenoid core 61, which r is lifted against its seat 62 with more or less force by a solenoid 63 according to the I strength of current flow through said solenoid. The solenoid 63 has one terminal connectedwith the line wire with which the battery terminal is directly connected and its other terminal is connected by a wire 64: with a switch contact 65 engaged by the motor starting switch 53 so that when the motor starting switch is closed the solenoid 63 receives practically the full voltage of the battery and closes the choke with considerable force and this condition continues as long as the starting switch is closed, that is during the cranking of the engine. This is notwithstanding the fact that the wire 64 includes a thermal switch 66 mounted on the engine, for such. switch is normally closed at the temperature of the engine when it is not running and alsonotwithstanding the presence in said wire 64 of a normally open switch 67 for the latter is closed whenever the motor starting switch 53 is closed. As shown, the switch 67 is closed by a solenoid coil 68 controlled by the motor starting switch 53 and it is retained in its closed position as long as the generator supplies a load on the mains by a solenoid coil 69 in the main line 12.

The degree of choking produced by the circuit closed through the solenoid 63 by the closing of the starting switch 53 is such as to be suitable for cranking the engine when it is cold and as soon as cranking is effected the starting switch in opened, automatically in practice, and the generator driven by the gas engine supplies the load on the mains. This, as before stated, retains switch 67 closed and current continues to flow through the choker circuit notwithstanding the opening of the starter switch for a resistance 70 is permanently connected between the terminals of the switch 53-65. Because of the resistance 7 0 introduced in the choker circuit,

' the flow of current is weaker and the choker system is idle prevents the choker circuit becoming re-established when the engine cools down and the thermal switch 67 closes,

It will be seen that by means of this invention the practice of fully choking the carbureter during cold weather cranking and continuing a partial choke until the engine is warm is automatically accomplished even in the case of automatically controlled electric generating units.

Another feature of the present invention is the function of the thermal switch, which prevents the operation of the choker whenever the engine is warm. A choker operating whenever the enginetis started is unsuit- By the use of this invention the battery is.

relieved ofa heavy duty incident to automatically repeated starts with a cold engine until the engine is capable of running without the choker. The automatic choke giving a full choking efi'ect during cranking and continuing a partial choke until the engine is warm, makes it possible for the automatic generating unit to respond promptly to the demand with a single cranking operation, even during cold weather conditions.

What I. claim as new and desire to secure by Letters Patent is:

1. In an internal combustion engine having a carbureter, means for choking the air intake to the carbureter, a solenoid for operating said choking means, an electric starter for the engine having a starting switch, a

circuit through the solenoid closed by the starting switch for making the choker effective when the starting switch is closed, means for continuing the circuit through the solenoid with added resistance after the startin switch is opened to make the choker partially effective, and means sensitive to the temperature of the engine for interrupting the solenoid circuit when the engine is warm.

2. In an internal combustion engine provided with a starter, solenoid means operating with the starter for choking the carbureter, means for weakening the solenoid for partially choking the carbureter after the starting operation, and means sensitive to the engine temperature for discontinuing the operation of the partial choking means when the engine is warm.

3. An internal-combustion-engine-driven generator capable of self starting, comprising a starting switch, a choker circuit including a magnetic choker controlled by the starting switch, a resistance interposed between the choker circuit contacts of the starting switch for continuing the choker circuit through such resistance when the starting switch is opened, a thermal switch sensitive to the temperature of the engine in the choker circuit for opening the choker circuit when the engine is warm, and an automatic switch in the choker circuit auto matically closed when the starting switch is closed and continuing closed during the operation of the generator but serving to automatically open the choker circuit when the generator is not operating.-

4. An internal-combusti0n-engine-driven generator, mains supplied thereby, a battery,

a starting switch for connecting the battery across the mains for starting the engine by the generator operating as a motor, a magnetic choker for the engine, a choker circuit including the choker and the' battery and closed by the starting switch, a. resistance connected between the choker circuit contacts of the starting switch to continue the choker circuit after the starting switch is opened, a thermal switch in the choker circuit sensitive to temperature conditions of the engine for opening the choker circuit when the engine is warm, and an automatic switch in the choker circuit closed by a solenoid coil controlled by the starting switch and held closed by a solenoid coil in the service mains but permitted to open the choker circuit when current ceases to flow through the service mains.

In testimony whereof, I afiix my signature.

ANTON FRANK BROTZ. 

